The semiconductor industry has experienced rapid growth due to continuous improvements in the integration density of various electronic components (i.e., transistors, diodes, resistors, capacitors, etc.). For the most part, this improvement in integration density has come from repeated reductions in minimum feature size, which allows more of the smaller components to be integrated into a given area.
These smaller electronic components also require smaller packages that utilize less area than previous packages. Some smaller types of packages for semiconductors include quad flat pack (QFP), pin grid array (PGA), ball grid array (BGA), flip chips (FC), three dimensional integrated circuits (3DICs), wafer level packages (WLPs), and package on package (PoP) devices. Package on package (PoP) technology is becoming increasingly popular for its ability to allow for denser integration of integrated circuits into a small overall package. In a package manufacturing process, forming openings for connectors plays a critical role. Therefore, the critical size of the opening for a package structure has drawn attention in the industry.